It is known to form a metal catalyst support by laying a corrugated strip upon a flat strip and then winding the double layer upon itself to form a spiral having axial channels for the flow of gas. This two strip construction has been described in U.S. Pat. Nos. 3,770,389, 3,891,575, in Society of Automotive Engineers Paper 770299, and in Platinum Metals Review, 21, No. 3, July, 1977. The two strip construction ensures that the spacing between successive layers in the spiral is uniform and that the axial channels are of uniform size. It would be advantageous to accomplish this uniformity in a spiral wound from a single strip, and that is one object of this invention.